DE10013828A1 - Metal process equipment or container for use in contact with vinyl monomers, e.g. distillation apparatus, has at least part of metal surface treated with polymeric complex former to prevent deposition of polymer - Google Patents

Abstract

A device in the form of technical process apparatus or a container with a metallic surface containing iron and/or molybdenum and/or vanadium and/or titanium and/or chromium and/or nickel and/or cobalt, has at least part of the surface treated with a polymeric complex-former (I). An Independent claim is also included for a method for the treatment of metallic surfaces by preparing a clean metallic surface and treating this with (I).

Description

The invention relates to a device that has a treated metallic Has surface and a method for treating the metallic Surface and its use.

When storing, manufacturing, refurbishing or further processing ethylenically unsaturated monomers such as styrene, (meth) acrylic acid, (Meth) acrylic acid esters and acrolein often encounter the problem of formation Deposits due to unwanted polymer formation on the walls of the relevant plant components. Such polymer deposits can Heat transport in the affected system parts, for example Container walls or on cooling devices of reactors or Distillers, significantly reduce. Polymer deposits in Pipelines, for example in distillers, can be closed Loss of pressure and / or blockages. The unwanted Polymer formation can take place until complete polymerization and thus lead to the solidification of mixtures containing these monomers. In addition, the undesirable polymer formation leads to losses of the concerned polymerizable, generally free-radically polymerizable compound. At Syntheses in which polymerizable compounds are used as starting material (e.g. in Michael addition) the undesirable polymer formation leads to a Reduction in yield.  

In order to prevent undesired polymer formation, soluble polymerization inhibitors are usually used. Such polymerization inhibitors are, on the one hand, known radical scavengers such as phenothiazine or phenols such as pyrogallol, hydroquinone or hydroquinone monomethyl ether, and on the other hand the salts of reversibly reducible / oxidizable metal cations, such as the pairs Cu ⁺ / Cu ²⁺ .

Soluble polymerization inhibitors have the disadvantage that they are the Can not completely suppress polymer formation on the container walls. High-boiling residues remain in the distillation of monomers Polymerization inhibitors in the template so that the distillate is not against Polymer formation is protected.

In the unpublished DE-A-198 08 179 dated February 26, 1998 describes inorganic coatings of process engineering plants, which prevent polymers from adhering to the interior walls in question should. The coated material contains immobilized metal ions and Oxygen compounds of boron, aluminum, silicon or phosphorus.

Another option is interior walls on which polymers separate can, by modification with organic protective layers to protect unwanted polymer deposition.

DE-A-196 48 811 describes the use of N-oxyl compounds by secondary amines to reduce polymeric deposits in the Polymerization of vinylically unsaturated compounds. The N-oxyl Compounds can either be added to the polymerization mixture or alternatively, the reactor surface can be added before the addition of the Polymerization mixture are wetted with N-oxyl compounds.

EP-B-0 606 013 relates to an inhibitor which affects the deposition of polymer Should reduce reactor surfaces during the polymerization. It is about  a low molecular weight condensation product from a Stilbene compound and a quinone compound, which before the polymerization in an alkaline solution is applied to the reactor wall. After this Drying creates a coating that is opposite polymeric deposits should protect during the polymerization.

Disadvantage of the above methods to provide a surface To protect unwanted polymer deposits is that on the surfaces generated protective layers are only resistant to certain media and the protective layers also lose their protective function over time.

The invention has for its object to provide a device with the polymerizable, in particular free-radically polymerizable compounds, e.g. As acrylic acid, can be distilled, stored or reacted without during distillation, storage or reaction polymer on the walls the corresponding device is deposited. This property is supposed to the device through the material and / or through the surface of the Device are caused. The material and / or the surface should not only be suitable for chemical processing plants before Protect adherence of polymer, but is also intended to protect the radical Inhibit polymerization in these plants.

The solution to this problem is based on a device that procedural apparatus or is designed as a container and a has metallic surface, the Fe and / or Mo and / or V and / or Ti and / or Cr and / or Ni and / or Co contains. The device according to the invention is characterized in that at least a portion of the metallic Surface is treated with a polymer complexing agent.

Under the metallic surface is the interface of a corresponding one The subject can be understood, this interface also as three-dimensional structure can be viewed - the surface is then the  top thin layer of a corresponding object (the thickness of the The surface is usually smaller than 1 mm). The treated metallic The surface usually forms the entire inner surface or a partial area of the surface Inner surface of a process engineering apparatus or a container. Process engineering apparatus can be devices, components and devices of all Be like z. B. pipelines, reactors, stirrers, seals or Separation devices (e.g. distillation equipment, filter presses, Centrifuges). Containers can be, for example, storage containers or storage containers his.

Polymeric complexing agents are to be understood as meaning compounds whose average molecular weight is at least 1000 g / mol, preferably between 3000 and 1.5 million g / mol (number average - gel permeation chromatography determination method), which also have coordination points at which heavy metals can be chemically bound, with an average of at least 8, preferably at least 12 coordination points (arithmetic mean) per molecule (per polymer). Coordination points are understood to be ligands or ligand groups which form coordinative bonds with metal ions under conditions of use - for example under the conditions of treatment with polymeric complexing agents, under conditions of storage, chemical synthesis, purification or material separation. Coordinative compounds are complexes that have at least one central atom or central ion and at least one ligand or ligand group (uncharged or negatively charged). Heavy metal ions mostly act as central ions. Important examples of coordination sites are bound oxygen-containing functional groups such as -COOH or -PO ₃ H ₂ and also nitrogen-containing functional groups, in particular five-membered or six-membered heterocycles containing nitrogen.

In particular, cations of Fe and / or Mo and / or V and / or Ti and / or Cr and / or Ni and / or Co complexed, that is coordinated,  can be. In principle, polymer complexing agents can also be used as salts available. Polymer complexing agents contain branched or unbranched Main chains (backbone), side chains pointing to the coordination points are bound.

In a preferred embodiment, the polymeric complexing agent contains phosphonoalkylated polyethyleneimines / polyvinylamines and / or carboxyalkylated polyethyleneimines / polyvinylamines and / or Vinylimidazole polymers. Form the groups of substances mentioned above Basic types of polymeric complexing agents in question. This Basic types will be described in more detail below.

Carboxyalkylated polyethyleneimines / polyvinylamines

Carboxyalkylated polyethyleneimines / polyvinylamines are polyethyleneimines / polyvinylamines in which hydrogen atoms of the secondary or corresponding to the primary amino functions are substituted by radicals which have carboxyl groups. Instead of the carboxyl groups, carboxylates can also be present at the corresponding points (deprotonated species) - then the carboxyalkylated polyethyleneimines / polyvinylamines are present as salts before polyethyleneimines can contain primary, secondary and / or tertiary amino functions. The primary or secondary amino groups can be completely or partially carboxyalkylated. In contrast to the secondary amino functions, in which naturally only one hydrogen atom can be substituted, one or two hydrogen atoms can be substituted in the primary amino functions. Linear or branched alkyl chains to which at least one COOR ¹ group (R ¹ stands for H or a metal ion, in particular Li, Na, K, Rb, Cs) are bonded as substituents for the nitrogen atoms in question. In addition to the COOR ¹ groups, these alkyl chains can also contain one or more other groups, in particular H, OH or PO ₃ R ² R ³ groups (R ² and R ³ are the same or different from one another and stand for H, or Metal ion, especially Li, Na, K, Rb or Cs).

Substituents of the general structure - (CH ₂ -) _n COOR ¹ are frequently bonded to the nitrogen atoms in question, where R ^{1 is} H or a metal ion, in particular Li, Na, K, Rb, Cs, and n = 1 to 10, preferably 1 or 2.

Carboxyalkylated polyethyleneimines / polyvinylamines can also Have structural units of any comonomer - but contain Polyethyleneimines / polyvinylamines at most 70% by weight, preferably at most 50 % By weight of structural units of such comonomers. The nitrogen atoms of the In principle, carboxyalkylated polyethyleneimines / polyvinylamines complete, partial (in the case of amino functions there is then a hydrogen atom substituted) and / or non-carboxyalkylated.

The molecular weight of the carboxyalkylated in question Polyethyleneimine / polyvinylamine is usually 1000 to 3,000,000 g / mol, preferably 3000 to 1,500,000 g / mol (number average - determination method: Gel permeation chromatography).

In particular come as carboxyalkylated polyethyleneimines / polyvinylamines carboxymethylated and carboxyethylated species in question.

A possible synthetic route for the production of carboxymethylated Polyethyleneimines / polyvinylamines should be listed below: Water-soluble polyethyleneimines / polyvinylamines I with the variable Molecular weights (usually number average from 1000 to 3,000,000 g / mol) can be in the alkaline variant of the Strecker reaction with sodium cyanide and carboxymethylate formaldehyde in a one-step synthesis.  

The intermediate stages II that occur are not isolated, but in the case of the in the reaction solution prevailing strongly alkaline pH Ammonia elimination directly to the N-carboxyalkyl polyimine III, that is, as a salt present carboxyalkylated polyethyleneimines / polyvinylamines, saponified. These polymeric complexing agents can be used, for example, as water-soluble Na Salts arise.

Carboxyethylated species can by Michael addition of acrylic acid or Acrylic acid esters are produced on polyethyleneimines / polyvinylamines, wherein ester groups can be subsequently hydrolyzed.

In particular come as carboxyalkylated polyethyleneimines / polyvinylamines carboxyalkylated polyethyleneimines as such and carboxyalkylated Polyvinylamines in question as such.

Carboxyalkylated polylysines, carboxyalkylated polyallylamines and carboxyalkylierce Poly-4-amino-styrenes are also said to be carboxyalkylated polymeric complexing agents are understood.

Carboxyalkylated polyethyleneimines / polyvinylamines have a high Binding ability for heavy metal ions.

Carboxyalkylated polyethyleneimines / polyvinylamines are preferably dissolved and / or used dispersed. Preferred solvent / dispersant is Water. Other solvents / dispersants - e.g. B. alcohols - are also  possible. They are in the corresponding solutions / dispersions carboxyalkylated polyethyleneimines / polyvinylamines mostly in concentrations from 0.001% to 70% by weight, preferably 0.1% to 15% by weight.

Phosphonoalkylated polyethyleneimines / polyvinylamines

Phosphonoalkylated polyethyleneimines / polyvinylamines are polyethyleneimines / polyvinylamines in which secondary or primary amino functions are phosphonoalkylated. Phosphonoalkylated polyethyleneimines / polyvinylamines can also be present as salts. Polyethyleneimines can contain primary, secondary and / or tertiary amino functions. The primary or secondary amino groups can be completely or partially carboxyalkylated. In contrast to the secondary amino functions, in which naturally only one hydrogen atom can be substituted, one or two hydrogen atoms can be substituted in the primary amino functions. Linear or branched alkyl chains in which at least one PO ₃ R ¹ R ² group (R ¹ and R ² are identical or different from one another and stand for H, or a metal ion, in particular Li, Na ⁾ are suitable as substituents for the nitrogen atoms in question. K, Rb or Cs) is bound. In addition to the PO ₃ R ¹ R ² groups, one or more other groups, in particular H, OH or COOR ³ groups (where R ³ stands for H or a metal ion, in particular Li, Na, K, Rb, Cs).

Often residues of the general structure - (CH ₂ -) _n PO ₃ R ¹ R ^{2 are} bound to the nitrogen atoms in question. R ¹ and R ^{2 are the} same or different from one another and stand for H, or a metal ion, in particular Li, Na, K, Rb or Cs, where n = 1 to 10, preferably 1 or 2.

Phosphonoalkylated polyethyleneimines / polyvinylamines can in addition to the phosphonoalkylated also carboxyalkylated primary or secondary Have amino functions.

Phosphonoalkylated polyethyleneimines / polyvinylamines can also Have structural units of any comonomer - but contain Polyethyleneimines / polyvinylamines at most 70% by weight, preferably at most 50 % By weight of structural units of such comonomers. Nitrogen atoms which are the can have phosphonoalkylated polyethyleneimines / polyvinylamines in principle completely, partially (in the case of amino functions then is a Hydrogen atom substituted) and / or not phosphonoalkylated.

The molecular weight of the phosphonoalkylated in question Polyethyleneimine / polyvinylamine is usually 1000 to 3,000,000 g / mol, preferably 3000 to 1,500,000 g / mol (number average - determination method: Gel permeation chromatography).

Particularly suitable phosphonoalkylated polyethyleneimines / polyvinylamines phosphonoalkylated polyethyleneimines as such and phosphonoalkylated Polyvinylamines in question as such. Phosphonoalkylated polylysines, phosphonoalkylated polyallylamines and phosphonoalkylated poly-4-amino Styrenes are also to be understood as phosphonoalkylated polymeric complexing agents become.

Phosphonoalkylated polyethyleneimines / polyvinylamines have a high Binding ability for heavy metal ions.

Phosphonoalkylated polyethyleneimines / polyvinylamines are preferably dissolved and / or used dispersed. Preferred solvent / dispersant is Water. Other solvents / dispersants - e.g. B. alcohols - are also possible. They are in the corresponding solutions / dispersions phosphonoalkylated polyethyleneimines / polyvinylamines mostly in concentrations from 0.001% to 70% by weight, preferably 0.1% to 15% by weight.  

Vinylimidazole polymers

Both vinylimidazole as such and substituted ones are said to be vinylimidazole Vinylimidazoles or vinylimidazole derivatives are understood.

Vinylimidazoles can be described by the following general structural formulas:

R ₁ , R ₂ , R ₃ , R ₄ , R ₅ and R ₆ can be identical or different from one another and represent hydrogen for branched or unbranched C ₁ -C ₁₂ alkyl radicals or for - (CH ₂ -CH ₂ -O- ) _n H, with n = 1 to 6.

Vinylimidazoles can also be present as a salt. Then, as shown by the structural formulas above, an anion X ^{- is} present in addition to the corresponding nitrogen-containing cation.

X ^- stands for any anion, in particular for F ^- , Cl ^- , Br ^- , J ^- , HSO ₄ ^- , O ₃ SOCH ₃ ^- , O ₃ SOCH ₂ CH ₃ ^- , O ₃ S-phenyl ^- , O ₃ S -4-methylphenyl ^- , H ₂ PO ₄ ^- , H ₂ PO ₃ ^- , H ₂ PO ₂ ^- , NO ₃ ^- or NO ₂ ^- .

Vinylimidazole polymers are homo- or copolymers based on the All of the structural units contained in them, at least 10% by weight, preferably have at least 50% by weight of vinylimidazole units. The remaining Structural units result from comonomers. The production of Vinylimidazole polymers thus take place by homo- or copolymerization of Vinyl imidazoles.

Vinylimidazole polymers which are derived from the homo- or Copolymerization of 1-vinylimidazole or of 1-vinyl-3-methyl imidazolinium chloride arise.

The following are particularly suitable as comonomers:
1-vinylimidazole, 1-vinyl-3-methyl-imidazolinium chloride, N-vinylformide, vinylamine, allylamine, 4-aminostyrene, vinylpyridine, vinyl acetate, vinyl propionate, acrylic acid, methacrylic acid, maleic acid, vinylphosphonic acid, N-vinylpyrrolidone or vinylcaprolactam.

The average molecular weight (number average: method of determination Gel permeation chromatography) of the candidate Vinylimidazole polymers is 1000 to 3,000,000 g / mol, preferably 3000 to 1,500,000 g / mol.

Vinylimidazole polymers have a high binding capacity for heavy metal ions. Vinylimidazole polymers are preferably used dissolved and / or dispersed. The preferred solvent / dispersant is water. Other Solvent / dispersant - e.g. B. alcohols - are also possible. In the The corresponding solutions / dispersions are usually the vinylimidazole polymers  in concentrations of 0.001% to 70% by weight, preferably 0.1% to 15% by weight, in front.

A major advantage of those treated with polymer complexing agents metallic surfaces is that on the latter the polymer formation and Adhesion of polymer can be inhibited. With polymeric complexing agents treated metallic surfaces are accordingly against formation and Deposition protected by polymer. Acrylic acid in particular can Distillation devices, the inner surfaces of which are polymeric Chelating agents have been treated without the appearance of being deposited Polyacrylic acid on the inner walls, can be distilled - without the appearance of Deposited polyacrylic acid or polymer on the inner walls can also mean that comparatively little is separated from it. A Distillation device designed according to the invention has at least Partial areas of the inner surface with polymeric complexing agents are treated.

The surfaces treated with polymer complexing agents can completely be designed differently. The latter can, for example, with the corresponding polymeric complexing agent can be coated or alternatively, for example, also have no coating.

According to the invention, a method for treating metallic surfaces is also provided. This contains the steps:

• a) providing a clean metallic surface and
• b) contacting the clean metallic surface with a polymer Complexing agent.

The provision of a clean metallic surface usually happens by cleaning an appropriate surface. For example, a Cleaning solution containing surfactants and phosphoric acid are used, in a second wash the latter with water from the surface  Will get removed. Contacting the clean metallic surface with a polymeric complexing agent is usually done by applying the polymeric complexing agent on the corresponding surface. The polymeric complexing agents in principle in different ways clean metallic surface. One way is polymeric complexing agent without solvent - according to the principle of Applying a powder coating - to bring to the surface. In a preferred embodiment, however, is dispersed and / or dispersed in liquid dissolved polymer complexing agent used. In practice, z. Legs metallic surface can be immersed in an appropriate solution that contains polymeric complexing agent - alternatively, of course, such a solution can also be sprayed onto the surface. The concentration of polymer Complexing agents in such solutions are usually 0.001 to 70% by weight, preferably 0.1 to 15% by weight. Depending on the solvent or dispersant polymeric complexing agent used in particular water or alcohols become. The polymeric complexing agent preferably contains phosphonoalkylated Polyethyleneimines / polyvinylamines and / or carboxyalkylated Polyethyleneimines / polyvinylamines and / or vinylimidazole polymers. In that case, that the polymeric complexing agent is dispersed and / or dissolved in liquid the metallic surface is applied - i.e. dispersed in liquid and / or contacted in solution with the metallic surface, is usually the Liquid after application or after contacting the surface away. This is preferably done by "letting it run" and / or by Dry.

According to the invention, containers and process engineering apparatuses are one have metallic surface according to that described above Process treated with polymeric complexing agent for the preparation, Separation, cleaning, implementation and / or storage of vinyl unsaturated compounds, ethers, aldehydes, ketones and / or peroxides used. Production, cleaning and implementation are particularly preferred and / or storage of vinylically unsaturated compounds known as acrylic acid  or as alkyl acrylates. The process engineering apparatuses are common trained as distillation facilities. It also lends with polymers Complexing agents treated metallic surface this treated surface Containing containers and process engineering apparatus protection against following substances or groups of substances: ethers such as dimethyl ether, diethyl ether, Tetrahydrofuran, polytetrahydrofuran, polyethylene glycol, polypropylene glycol; Glycols such as ethylene glycol, propylene glycol; Aldehydes such as acetaldehyde, Formaldehyde, glutardialdehyde, acrolein, butyraldehyde, isobutyraldehyde; Ketones such as acetone, ethyl methyl ketone, 3-methyl-2-butanone, mesityl oxide; Peroxides like Hydrogen peroxide, di-tertiary butyl peroxide, dibenzyl peroxide, tertiary butyl hydroperoxide, cumyl hydroperoxide, peracetic acid.

Generally gives the metallic treated with polymer complexing agents Surface protection from the material below the surface substances sensitive to oxidation.

In the following, the invention will be described in more detail using exemplary embodiments to be discribed.

Comparative example Only cleaned stainless steel nets

A stainless steel mesh is placed in an aqueous solution at room temperature for 15 minutes Cleaning solution containing phosphoric acid and surfactants dipped and then immersed in demineralized water for 15 minutes and then at Room temperature dried.

example 1 Treated stainless steel nets

Two stainless steel grids (grids A and B) are placed in one at room temperature for 15 min cleaning solution containing aqueous phosphoric acid and surfactants and then immersed in demineralized water for 15 minutes. Then they will Stainless steel nets 15 min in a solution consisting of 5 wt .-% unsubstituted  Polyvinylimidazole (average molecular weight = 50,000 g / mol - Determination method: light scatter) and 95% by weight of fully demineralized water dipped and then dried at room temperature.

Example 2 Treated stainless steel nets

Two stainless steel grids (grids A and B) are placed in one at room temperature for 15 min cleaning solution containing aqueous phosphoric acid and surfactants and then immersed in demineralized water for 15 minutes. Then they will Stainless steel nets 15 min in a solution consisting of 5 wt .-% of a Copolymers of the composition 50% by weight of N-vinylpyrolidone and 50% by weight % 1-vinyl-3-methylimidazolinium chloride and 95 wt .-% fully desalinated Dipped in water and then dried at room temperature.

Example 3 Treated stainless steel nets

A stainless steel mesh is placed in an aqueous solution at room temperature for 15 minutes Cleaning solution containing phosphoric acid and surfactants dipped and then immersed in demineralized water for 15 minutes. Then it will Stainless steel net 15 minutes in a solution consisting of 5% by weight carboxymethylated polyethyleneimine (average degree of polymerization = 500; Number average determined by gel permeation chromatography, approx. 82% of the Nitrogen atoms are carboxymethylated), the carboxyl groups of which Sodium carboxylate groups are present, and 95% by weight of fully demineralized water dipped and then dried at room temperature.

Example 4 Treated stainless steel nets

A stainless steel mesh is placed in an aqueous solution at room temperature for 15 minutes 3 Cleaning solution containing phosphoric acid and surfactants dipped and then immersed in demineralized water for 15 minutes. Then it will Stainless steel net 15 minutes in a solution consisting of 5% by weight  phosphonomethylated polyethyleneimine (average degree of polymerization = 500; Number average determined by gel permeation chromatography, approx. 80% of the Nitrogen atoms are phosphonomethylated), the phosphonate groups of which Sodium phosphonate groups are present and 95% by weight of fully demineralized water dipped and then dried at room temperature.

Test and result of the inhibitory effect

To test the inhibitory effect - inhibition of formation or Deposition of polymer - the stainless steel nets are in the steam room Distillation apparatus, in which there is refluxing acrylic acid. The acrylic acid refluxed at 0.1 bar pressure with a boiling temperature of 90 ° C. The nets are installed in the equipment in such a way that Acrylic acid vapor as well as with acrylic acid condensate are in contact. Rated the amount of polymeric deposits on the nets after 7 h stay in the refluxing acrylic acid. The following table shows the results.  

The following stainless steel nets were used in all experiments: size 40 × 20 mm, mesh size 1.6 mm, diameter of the wires 0.5 mm, Stainless steel composition - figures in mol.%: 0.08 C, 1 Si, 2 Mn, 0.045 P, 0.03 S, 17-19 Cr, 9-12 Ni, 0.4 Ti, remaining amount of Fe.

The results shown in the two tables above show that by treating the metallic surface with polymers Complexing agents significantly reduce the formation or adhesion of polymer can be. It is shown that this can be achieved by using phosphonomethylated polyethyleneimines / polyvinylamines, carboxymethylated polyethyleneimines / polyvinylamines and Vinylimidazole polymers succeed as polymeric complexing agents. The Inhibition of unwanted polymer formation or polymer deposition by the provision of surfaces treated with polymer complexing agents will be shown.

Claims (10)

1. A device which is designed as a process engineering apparatus or as a container and has a metallic surface which contains Fe and / or Mo and / or V and / or Ti and / or Cr and / or Ni and / or Co, characterized in that that at least a portion of the metallic surface is treated with a polymer complexing agent. 2. Device according to claim 1, characterized in that the polymer Complexing agent phosphonoalkylated polyethyleneimines / polyvinylamines and / or carboxyalkylated polyethyleneimines / polyvinylamines and / or Contains vinylimidazole polymers. 3. A method for treating metallic surfaces according to claim 1 or 2, comprising the steps:

• a) providing a clean metallic surface and
• b) contacting the clean metallic surface with a polymeric complexing agent.

4. The method according to claim 3, characterized in that for Performing step (a) the metallic surface is cleaned. 5. The method according to claim 3 or 4, characterized in that the polymeric complexing agents phosphonoalkylated polyethyleneimides ne / polyvinylamines and / or carboxyalkylated polyethyleneimines ne / contains polyvinylamines and / or vinylimidazole polymers.   6. The method according to any one of claims 3 to 5, characterized in that when performing step (b) in liquid and / or dissolved polymer complexing agent is used. 7. The method according to claim 6, characterized in that the liquid is removed from the surface after performing step (b). 8. Use of containers and process engineering equipment, the one have metallic surface, which is partially or completely by the Method according to one of claims 3 to 7 with polymer Complexing agent is treated, for production, separation, cleaning, Reaction and / or storage of vinylically unsaturated compounds, Ethers, glycols, aldehydes, ketones and / or peroxides. 9. Use according to claim 8, characterized in that the vinyl unsaturated compounds as acrylic acid or as alkyl acrylates available. 10. Use according to claim 8 or 9, characterized in that the Process engineering apparatus designed as distillation devices are.